A U.S. Marine and Afghanistan war veteran held in a Mexico prison for nearly two months will make appearance in court Wednesday, his mother told CNN's "New Day.

Jill Tahmooressi said her son, Marine Sgt. Andrew Tahmooressi, accidentally crossed into Mexico with three personal firearms - all bought legally in the U.S.

The 25-year-old had intended to drive to meet friends in San Ysidro, California, on March 31, and was moving from Florida to California in the hope of settling, getting a job and continuing treatment he had just begun for post traumatic stress related to his two combat tours.

With all his possessions in his truck, Tahmooressi drove across the border. When he realized his mistake, his mother said, he dialed 911 and asked the operator to help him. No help came, Jill Tahmooressi said. Her son first encountered Mexican customs agents, she said, and he believed they understood that he'd made an innocent error. They seemed to be getting an escort car to help him, she said.

But the officers with the Mexican military interfered, she told "New Day," and her son was arrested.

"He is relieved that he'll be able to go before the judge and explain precisely how he made that accidental wrong turn and ended up in the dilemma that he's in right now," she said.

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